In some vehicles a spare wheel is held beneath the chassis of the vehicle by means of a spare-wheel pick-up system. The system includes a support shaft on which is supported the wheel, a cable fixed to the support shaft and a mechanism to cause the cable to move up or down to raise or lower the spare wheel. Generally speaking, additionally, when the wheel is held beneath the chassis of the vehicle, the cable is wound onto a drum.
It is known that on occasions, due mainly to the vibrations the vehicle has to withstand, the cable unwinds from or comes off the drum, with the risk that the support shaft, and therefore the wheel, falls. It may also be the case that the cable snaps, due to vibrations or to the fact that the wheel is improperly tightened on the chassis